Method and system for position updating using cached radio signal range

ABSTRACT

Systems and methods for position updating for a mobile device are disclosed. A mobile device receives a first position data at a first time and queries for network information associated with a serving cell of a cellular network. The network information contains a radio signal level associated with the serving cell of the cellular network. The mobile device compares the radio signal level against a previously stored radio signal range received from a network server and determines a position updating opportunity for the mobile device based on the comparison. The network server assists the position updating process by acquiring, positioning data from a plurality of mobile devices operating in the cellular network. The network server determines a QoP information based on the acquired positioning data and transmits the QoP information to the plurality of mobile devices to be stored for position update.

CROSS REFERENCE TO RELATED APPLICATION

This claims the benefit of commonly-assigned U.S. Provisional PatentApplication No. 61/991,909, filed May 12, 2014, which is herebyincorporated by reference herein in its entirety.

FIELD OF USE

This disclosure relates to field of positioning technology for mobiledevices.

BACKGROUND

The background description provided herein is for the purpose ofgenerally presenting the context of the disclosure. Work of theinventors hereof, to the extent the work is described in this backgroundsection, as well as aspects of the description that may not otherwisequalify as prior art at the time of filing, is neither expressly norimpliedly admitted as prior art against the present disclosure.

A cellular network is any mobile communications network with a series ofoverlapping hexagonal cells in a honeycomb pattern. Mobile devices in acellular network often need to access their position data on a real-timebasis in order to support the location-based services and applicationsimplemented on these devices. Conventionally, the current position ofthe mobile devices can be determined with a Global Navigation SatelliteSystem (GNSS), such as a Global Positioning System (GPS) chipset. Themobile devices would query the navigation service, either at regularintervals or when the devices have been moved, to request updatedposition data.

However, this arrangement places considerable burden on the systemresources of the mobile devices. Constant and regular queries to thenavigation service are expensive operations (in terms of power andcommunication bandwidth consumption) to carry out over a prolongedperiod of time. Similarly, sending a query to the navigation servicewhenever the mobile devices are moved (e.g., as detected by an on-boardaccelerometer) could result in unnecessary queries, especially if themobile devices are simply oscillating about the same location.

SUMMARY

Systems and methods for position updating for a mobile device areprovided. In some embodiments, a mobile device receives first positiondata at a first time and queries for network information associated witha serving cell. The network information contains a radio signal levelassociated with the serving cell. The mobile device compares the radiosignal level against a previously stored radio signal range receivedfrom a network server and determines a position updating opportunity forthe mobile device based on the comparison.

In some embodiments, the mobile device determines the position updatingopportunity by determining whether the radio signal level is within thepreviously stored radio signal range. In response to determining thatthe radio signal level is not within the previously stored radio signalrange, the mobile device receives second position data at a second time.In some embodiments, the first position data and the second positiondata are received in response to a request to the network server.

In some embodiments, a dwell time is calculated based on the first timeand a timestamp of detecting the serving cell. In response todetermining that the dwell time exceeds a predetermined timingthreshold, the mobile device receives second position data. In someembodiments, the previously stored radio signal range is calculated atthe network server and temporarily stored on the mobile device. In someembodiments, the mobile device queries for the network information byscanning radio signal data broadcast from a cell tower located withinthe serving cell.

Systems and methods for a network server to assist position update formobile devices are also provided. In some embodiments, the networkserver acquire positioning data from a plurality of mobile devicesoperating in a cellular network, determines a Quality-of-Position (QoP)information based on the acquired positioning data and transmits the QoPinformation to the plurality of mobile devices to be stored for positionupdate. In some embodiments, the QoP information includes radio signalrange data. In some embodiments, the acquired positioning data comprisesposition data received from a GNSS and network information stored on theplurality of mobile devices. In some embodiments, the network serverdetermines the QoP information by statistically analyzing the acquiredpositioning data.

In still some other embodiments, the network server transmits the QoPinformation in response to determining that the mobile device does notsupport GNSS functionality or that the mobile device's GNSSfunctionality is inaccessible.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features of the disclosure, its nature and various advantages,will be apparent upon consideration of the following detaileddescription, taken in conjunction with the accompanying drawings, inwhich like reference characters refer to like parts throughout, and inwhich:

FIG. 1 illustrates an example of a server-based positioning platformthat provides position data to mobile devices according to an embodimentof this disclosure;

FIG. 2 is a flow chart of a mobile device carrying out a positionupdating process according to an embodiment of this disclosure;

FIG. 3 is a flow chart for a server to determine radio signal rangeinformation according to an embodiment of this disclosure;

FIG. 4 shows a block diagram of an exemplary mobile device according toan embodiment of this disclosure; and

FIG. 5 is another flow chart of a mobile device carrying out a positionupdating process in accordance with an embodiment of this disclosure.

DETAILED DESCRIPTION

Various implementations of this disclosure provide an enhanced mechanismto assist mobile devices in determining and updating their currentphysical location. Rather than relying on a GNSS such as the GPS, theGLObalnaja NAvigatsionnaja Sputnikovaja Sistema (GLONASS), the Galileonavigation satellite system, the Beidou navigation satellite system, andthe like, mobile devices can utilize network information in a mannerdescribed herein to deduce their current location. For instance, mobiledevices in a cellular network regularly receive radio signals from thecellular tower. Oftentimes, the mobile devices utilizes the receivedradio signals to perform various cellular functions, such as sending andreceiving text messages. When prompted, the mobile devices mayadditionally provide their location information to a remote server ofthe cellular network, which calculates a radio signal range based on astatistical model. The radio signal range can be delivered to the mobiledevices within the cellular network to be cached and used to determineand update their location information. It is understood that the terms“cached” and “stored” refer to saving a value into a memory or storageelement. Further details of implementing systems and method of positionupdating based on cached radio signal range will be made apparent inview of the following description.

FIG. 1 illustrates an example of a server-based positioning platformthat provides position data to mobile devices according to an embodimentof this disclosure. Platform 100 includes a server 160 and severalexemplary cellular networks, such as a Wideband Code Divisional MultipleAccess (WCDMA) network 110,a 4G Long-Term Evolution (LTE) network 120, aCDMA 2000 network 130, and a Global System for Mobile Communications(GSM)/General Packet Radio Service (GPRS) network 140. Each of thesenetworks may involve one or more mobile devices, such as devices 112,122, 132, and 142, respectively. It is understood that any one or moreof networks 110, 120, 130, and 140 may be coupled to server 160 via theInternet. Additionally, mobile devices 102 may also be connected to theInternet via WiFi to communicate with server 160. Mobile devices 102,112, 122, 132, and 142 may support GNSS functionality by incorporating asatellite navigation chipset, such as a GPS chipset. Mobile devices thatsupport GNSS functionality are able to determine their current locationinformation by querying the corresponding navigation service.

The mobile devices of FIG. 1 collect and store network informationassociated with a serving cell in the cellular network. The networkinformation may contain a cell global identity (CGI), a radio signallevel, and an event timestamp used to identify events in the servingcell. The CGI includes a mobile country code (MCC), a mobile networkcode (MNC), a location area code (LAC), and a cell identity (CI). Asdescribed herein, the serving cell is a cell that providestelecommunication and/or data services to the subject mobile device inthe cellular network. A suitable serving cell is one that providessignals with high signal-to-noise ratio (SNR) to a given mobile deviceand reliable communication links that can be utilized by applicationsrunning on the mobile device.

In one embodiment, server 160 may include a data engine (DE) server 162,a position engine (PE) server 164, and a position database 166. DEserver 162 processes positioning data submitted by one or more of mobiledevices that support GNSS functionality. The positioning data canassociate position coordinates of a location with network informationfor providing telecommunication and/or data services at the location. Inaddition, DE server 162 maintains the processed positioning data inposition database 166. Position database 166 stores the positioning datasubmitted by the mobile devices. In some embodiments, position database166 may organize the positioning data in a hierarchical folderstructure. In the event that a mobile device does not support GNSSfunctionality, or that a mobile device's GNSS functionality is notaccessible, PE server 164 provides, upon request, the mobile device'scurrent position to the mobile device based on a position calculationfunction. PE server 164 may additionally transmit Quality of Position(QoP) information to the mobile device in order to assist the mobiledevice in updating its current position.

The position calculation function implemented on PE server 164calculates position data for a mobile device using the networkinformation based on positioning data received from a plurality ofmobile devices within the same cellular network. The position data maybe stored in a networked storage medium, such as position database 166,and then transmitted to the mobile device for local storage.Alternatively, the position data may be stored locally on the mobiledevice itself. The position data may include position coordinates(latitudinal and longitudinal), uncertainty values associated with theposition coordinates, and QoP information. The locally-stored positiondata can be stored in a local database used to store other device data,such as application runtime data, financial transaction data,audio/video data, and image data. Alternatively, the locally-storedposition data can be stored in a dedicated database, such as locationhistory database 485 of FIG. 4.

A number of communication protocols and interfaces may be utilized totransmit position data from PE server 164 to a mobile device, such ashypertext transfer protocol (HTTP), transmission controlprotocol/Internet protocol (TCP/IP), user datagram protocol (UDP), andwireless application protocol (WAP), and any other protocols suitablefor data communication using the Internet. By default, communication ofposition data occurs on the HTTP interface of the mobile device.

When a mobile device is within a serving cell of a cellular network, themobile device can query PE server 164 to request position data forapplications running on the mobile device. In particular, QoPinformation may be used to determine whether a position update isnecessary. In some embodiments, the QoP information is a range of radiosignal determined at PE server 164 and cached at the mobile device. TheQoP information is determined based on the positioning data contributedby the mobile devices in the past.

When a mobile device applies the cached QoP information (i.e., thecached radio signal range) to the calculation of position updates, themobile device makes a determination of whether its current radio signallevel is within the cached radio signal range. If the current radiosignal level is outside of the cached radio signal range, the mobiledevice will initiate position updating. On the other hand, if thecurrent radio signal level is within the cached radio signal range, themobile device is considered to be at the same position as its lastupdated position.

FIG. 2 is a flow chart of a mobile device, such as one of mobile devices102, 112, 122, 132, and 142, carrying out a position updating process inaccordance with an embodiment of the present disclosure. Process 200 canbe performed by one or more processors or processing cores on the mobiledevice. Process 200 may also include multiple sub-processes or threadson the processors of the mobile device. Part of process 200 may becarried out by a device other than the mobile device itself, such as bya network server. Process 200 begins at 201 and proceeds to 210.

At 210, the mobile device receives first position data at a first time.The first position data may be received from a network server, such asPE server 164, via the Internet.

The mobile device may actively and regularly scan for networkinformation broadcast from a cell tower located within a serving cell ofa cellular network. As discussed in relation to FIG. 1, the networkinformation queried for by the mobile device may include CGIinformation, a radio signal level, and an event timestamp used toidentify events in the serving cell. Specifically, the mobile device canquery PE server 164 to request position data according to the scannednetwork information.

At 220, after a predetermined time interval, the mobile device queriesfor network information associated with the serving cell of the cellularnetwork.

At 230, the query for network information may be used in searching aposition history database (e.g., location history database 485 in FIG.4) of the mobile device for past CGI information. If past CGIinformation cannot be found in the position history database, process200 proceeds to 260, whereby the mobile device may initiate a positionupdate request immediately and receive second position data at a secondtime. On the other hand, if past CGI information is found in theposition history database, the mobile device will retrieve the searchresult, which includes cached QoP information and a timestamp associatedwith the acquisition of the first position data (i.e., the first time),and proceeds to 240.

At 240, the mobile device compares the radio signal level against thecached QoP information. As discussed in relation to FIG. 1, the QoPinformation is a radio signal range that can be received and stored bythe mobile device.

At 250, the comparison of the radio signal level against the cachedradio signal range can be used to determine a position updatingopportunity for the mobile device. For instance, if the radio signallevel is −50 dBm and the cached radio signal ranges from −45 dBm to −60dBm, the radio signal level is within the cached radio signal range andposition updating is unnecessary. In this instance, as illustrated at270, the mobile device can remain at its current position and does notinitiate a position update. In another example, if the radio signallevel is −65 dBm and the cached radio signal still ranges from −45 dBmto −60 dBm, the radio signal level falls outside of the cached radiosignal range. In this instance, at illustrated at 260, the mobile devicemay initiate a position update.

At 260, the mobile device receives second position data at a secondtime. The second position data is received from a network server, suchas PE server 164, via the Internet. Specifically, the mobile device canquery PE server 164 to request position data according to the query fornetwork information.

At 270, the mobile device can remain at the first position. In anexample, the mobile device disables any position updating request,thereby remaining in a power-saving mode.

In some embodiments, the mobile device at a time may passively receivethe network information broadcast from a cell tower located within aserving cell of a cellular network. It should be noted that, even if theradio signal level falls outside of the cached radio signal range, themobile device may still opt to not initiate a position update becausethe dwell time of the position updating opportunity has not exceeded apredetermined timing threshold, whereby the dwell time refers to thetime difference between receiving the first position data (i.e., thefirst time) and a timestamp for detecting the serving cell. This couldbe due to the fact that none of the candidate positions offers a betterlocation service for the application running on the mobile device. Forexample, the second position may be extremely close to the firstposition, or the uncertainty value associated with the second positionmay be too high such that the second position is unreliable.

At 299, process 200 terminates.

FIG. 3 is a flow chart for a server to determine QoP information (i.e.,calculating the radio signal range) according to an embodiment of thisdisclosure. Process 300 can be performed by one or more processors orprocessing cores on a server, such as server 160 of FIG. 1. Process 300may also include multiple sub-processes or threads on the processors ofthe server. At 301, process 300 begins.

At 310, the server acquires positioning data from one or more mobiledevices operating in a cellular network. In some embodiments, thepositioning data acquisition is performed by a data engine such as theDE engine server of server 160 in FIG. 1. The positioning data acquiredby the server may include location information collected during a GNSSevent and network information stored on the mobile device. In someembodiments, the positioning data is collected and stored by the mobiledevice with a software or firmware running by a processor on the mobiledevice. In some embodiments, the positioning data collection process onthe mobile device can be initiated in response to a trigger event. Insome other embodiments, the positioning data may be acquired by theserver (e.g., uploaded to the server) either according to a schedulingalgorithm or in response to another triggering event.

At 320, the server determines a QoP information based on the acquiredpositioning data. The QoP information can be determined based on astatistical analysis of the radio signal data (e.g., a cumulativedistribution function). It is understood that other statisticalcalculations on the radio signal data are possible and are well withinthe scope of the present disclosure. As described above in relation toFIGS. 1 and 2, the QoP information, in some embodiments, is a radiosignal range.

At 330, the server transmits the QoP information to the mobile device inorder to assist the mobile device in executing the position update. Themanner in which the mobile device performs the position update based onthe QoP information is illustrated above in relation to FIG. 2. At 399,process 300 terminates.

FIG. 4 shows a block diagram of an exemplary mobile device as usedaccording to an embodiment of this disclosure. Mobile device 400 may beany of devices 102, 112, 122, 132, and 142. For instance, mobile device400 may be a smartphone, an electronic tablet, or a handheld computer.

The architecture of mobile device 400 comprises five layers, namely, anapplication layer 490, an application framework layer 480, a hardwareabstraction layer 470, a kernel driver layer 460, and a hardware layer450. Each layer may be implemented in hardware, firmware, software, orany combination thereof, using control circuitry and input/outputcircuitry.

Application layer 490 may optionally include a GNSS setting/listeningmodule 491 and a coarse location setting/listening module 492. Once theGNSS setting/listening module 491 and the coarse positionsetting/listening module 492 have been initialized, mobile device 400may send a request to verify its current position. For example, when theGNSS setting/listening module 491 is initialized, the current positionof mobile device 400 can be determined based on the GNSS system and thedetermined position is provided to the application layer 490. When thecoarse location setting/listening module 492 is initialized, the currentposition of mobile device 400 can be determined based on the cellularand/or wireless local area network (WLAN) radio signal data and thedetermined position is provided to the application layer 490.

Application framework layer 480 comprises a location manager service 489to manage position requests and responses, as well as submission ofpositioning data to the DE server 162. Location manager service 489 mayoptionally include a GNSS position provider 481 and a network positionprovider 482. GNSS location provider 481 processes position requests andresponses associated with a GNSS event. For example, GNSS locationprovider 481 communicates, using GNSS signals, with a navigation serviceto request and receive a current position for mobile device 400. Networklocation provider 482 processes position requests and responsesassociated with a network server, such as by using radio signals in acellular network or a WLAN. Network location provider 482 may optionallyinclude a data kit (DataKit) 483, profile-based position provider 420, adata interface 484, a location history database 485, and a staticprofile determination module 410. The profile-based position provider420 further includes a server location kit (SLocKit) 430, a clientlocation kit (CLocKit) 440.

In some embodiments, DataKit 483 may opt to collect position data fromGNSS location provider 481 and merge radio signal data with GNSSposition data based on filtering criteria. In some embodiments, theradio signal data can be any radio signal received from the cellulartower, which may include network information. In some other embodiments,the radio signal data can be any radio signals received from WLAN. Onceposition data collection and merge are complete, DataKit 483 compilesthe merged data to submit to DE server 162 via an applicationprogramming interface (API). In some embodiments, SLocKit 430 collectsscanned cellular/WLAN radio signals and sends the scanned signals to PEserver 164 via API in order to request and receive position informationof mobile device 400. In some embodiments, CLocKit 440 collects scannedWLAN radio signals and sends the scanned signals to memory 475 in orderto retrieve WLAN supplementary data. Based on the retrieved WLANsupplementary data, CLocKit 440 determines the current position ofmobile device 400. Location history database 485 stores positioninformation received from SLocKit 430 or CLocKit 460. In someembodiments, data interface 484 allows each and every data kit innetwork location provider 482 (i.e., DataKit 483, SLocKit 430, andCLocKit 440) to initiate and terminate capturing of the radio signaldata.

Hardware abstraction layer 470 may optionally include a GNSS processor471, a radio processor 472, and a WLAN processor 473. Hardwareabstraction layer 470 may optionally include a memory interface 474 anda memory 475. In some embodiments, the memory interface 474 receives theWLAN supplementary data from PE server and sends the received data tomemory 475. Memory 475 stores the WLAN supplementary data under ahierarchical folder structure. In some embodiments, processors 471, 472,and 473 can be implemented as software (or firmware) and interface withhardware layer 450 (i.e., a GNSS chipset 451, a radio chipset 452, and aWLAN chipset 453) via kernel driver 460. The hardware layer 450 may alsoinclude MEMS sensors 454 configured to sense motion of mobile device400. The MEMS sensors 454 can include any suitable sensors, such as athree-axis accelerometer, to sense motion of mobile device 400. Thesensor data is provided to the static profile determination module 410via a register (not shown).

As made apparent in the foregoing description, position requests andresponses between a server-based positioning platform (e.g., Platform100 of FIG. 1) and a mobile device (e.g., Mobile Device 400 of FIG. 4)can be implemented on any cellular network using pull operations, pushoperations, automatic data exchanges, and any combination thereof, byway of one or more communication interfaces. As described in relation toFIG. 1, the mobile device could be one that supports GNSS functionalityor one that does not support GNSS functionality. The one or morecommunication interfaces can be HTTP, TCP/IP, UDP, WAP, or any othersuitable communication protocols.

Position requests from the mobile device and response messages from theserver can be implemented in HTTP GET and HTTP POST commands. When thedefault command of HTTP POST is used, the position requests and responsemessages may include data payload (i.e., in the body of the message).The data payload carried in an HTTP POST request can be transmitted in astandard format, such as Extensible Markup Language (XML), JavaScriptObject Notation (JSON), or any other customized format. By default, theformat used by the system described herein is XML, whereby the datapayload can be text, integers, or floating point numbers. In someembodiments, once the server has successfully processed a positionrequest, a status code of 200 (OK) will be generated as thecorresponding response message. If the petition request is notsuccessfully processed, the server will, instead, generate a responsemessage indicating an error message.

FIG. 5 is another flow chart of a mobile device carrying out a positionupdating process (i.e., Process 500) in accordance with an embodiment ofthis disclosure.

At 510, the mobile device receives first position data at a first time.At 520, after a predetermined time interval, the mobile device queriesfor network information associated with the serving cell of the cellularnetwork. At 530, the mobile device compares the radio signal level (fromthe queried network information) against the cached QoP information. At540, the comparison of the radio signal level against the cached radiosignal range can be used to determine a position updating opportunityfor the mobile device.

The foregoing describes methods and systems for position updating usingcached radio signal range. Any embodiments as described in thisdisclosure can be implemented in software by, for example, encodinginstructions for performing the processes (e.g., Process 200 and Process300) discussed above in one or more computer-readable media. It will beunderstood that the foregoing is only illustrative of the principles ofthe disclosure, and that the disclosure can be practiced by other thanthe described embodiments, which are presented for purposes ofillustration and not of limitation, and the present disclosure islimited only by the claims which follow.

What is claimed is:
 1. A method for position updating for a mobiledevice, the method comprising: receiving, with the mobile device, firstposition data corresponding to a location of the mobile device at afirst time; querying, using the mobile device, for network informationassociated with a serving cell, wherein the network information containsa radio signal level associated with the serving cell; comparing theradio signal level against a previously stored radio signal rangereceived from a network server; determining whether the radio signallevel is within the previously stored radio signal range; and refrainingfrom requesting position update using the mobile device in response todetermining that the radio signal level is within the previously storedradio signal range.
 2. The method of claim 1, further comprising: inresponse to determining that the radio signal level is not within thepreviously stored radio signal range, requesting position update withthe mobile device in order to receive second position data.
 3. Themethod of claim 2, wherein the first position data and the secondposition data are received in response to a request to the networkserver.
 4. The method of claim 1, further comprising: calculating adwell time based on the first time and a timestamp of detecting theserving cell; and in response to determining that the dwell time exceedsa predetermined timing threshold, receiving, with the mobile device,second position data.
 5. The method of claim 1, wherein the previouslystored radio signal range is calculated at the network server andtemporarily stored on the mobile device.
 6. The method of claim 1,wherein the querying for the network information further comprisesscanning radio signal data broadcast from a cell tower located withinthe serving cell.
 7. A method for assisting position update for mobiledevices, the method comprising: acquiring, with a network server,positioning data from a plurality of mobile devices operating in acellular network, the positioning data corresponding to locations of theplurality of mobile devices; determining a Quality-of-Position (QoP)information based on the acquired positioning data; transmitting, fromthe network server, the QoP information to the plurality of mobiledevices to be compared against a plurality of radio signal levelsassociated with the plurality of mobile devices; and receiving, from theplurality of mobile devices, requests for position update based on thetransmitted QoP information.
 8. The method of claim 7, wherein the QoPinformation includes radio signal range data.
 9. The method of claim 7,wherein the acquired positioning data comprises position data receivedfrom a Global Navigation Satellite System (GNSS) and network informationstored on the plurality of mobile devices, and wherein the QoPinformation is determined, at the network server, by statisticallyanalyzing the acquired positioning data.
 10. The method of claim 9,wherein the transmitting occurs in response to determining that themobile device does not support GNSS functionality or that the mobiledevice's GNSS functionality is inaccessible.
 11. A mobile device capableof updating position, the mobile device comprising: input/outputcircuitry configured to: receive first position data corresponding to alocation of the mobile device at a first time; and query for networkinformation associated with a serving cell, wherein the networkinformation contains a radio signal level associated with the servingcell; and control circuitry configured to: compare the radio signallevel against a previously stored radio signal range received from anetwork server; determine whether the radio signal level is within thepreviously stored radio signal range; and refrain from requestingposition update using the mobile device in response to determining thatthe radio signal level is within the previously stored radio signalrange.
 12. The mobile device of claim 11, wherein the control circuitryis further configured to: in response to determining that the radiosignal level is not within the previously stored radio signal range,request position update with the mobile device in order to receivesecond position data.
 13. The mobile device of claim 12, wherein thefirst position data and the second position data are received by theinput/output circuitry in response to a request to the network server.14. The mobile device of claim 11, wherein the control circuitry isfurther configured to: calculate a dwell time based on the first timeand a timestamp of detecting the serving cell; and receive secondposition data in response to determining that the dwell time exceeds apredetermined timing threshold.
 15. The mobile device of claim 11,wherein the previously stored radio signal range is calculated at thenetwork server and temporarily stored on the mobile device.
 16. Themobile device of claim 11, wherein the input/output circuitry is furtherconfigured to query for the network information by scanning radio signaldata broadcast from a cell tower located within the serving cell.
 17. Asystem for assisting position update for mobile devices, the systemcomprising: a position database to store positioning data correspondingto locations of a plurality of mobile devices operating in a cellularnetwork; a data engine server configured to acquire the positioning datafrom the plurality of mobile devices; and a position engine serverconfigured to: determine a Quality-of-Position (QoP) information basedon the acquired positioning data; transmit the QoP information to theplurality of mobile devices to be compared against a plurality of radiosignal levels associated with the plurality of mobile devices; andreceive, from the plurality of mobile devices, requests for positionupdate based on the transmitted QoP information.
 18. The system of claim17, wherein the QoP information includes radio signal range data. 19.The system of claim 17, wherein the acquired data comprises positioningdata received from a Global Navigation Satellite System (GNSS) andnetwork information stored on the plurality of mobile devices, andwherein the QoP information is determined by statistically analyzing theacquired positioning data.
 20. The system of claim 19, wherein theposition engine server is further configured to transmit the QoPinformation in response to determining that the mobile device does notsupport GNSS functionality or that the mobile device's GNSSfunctionality is inaccessible.